Method of and apparatus for forming an ingot of molten reactive material



June 18, 1963 G. A. PAGoNls METHOD OF' AND APPARATUS FOR FORMING AN INGOT OF MOLTEN REACTIVE MATERIAL 3 Sheets-Sheet l Filed Sept. 30, 1959 VALVE LCKED [VALVE l/NLCKE IN VEN TOR George Il. Pagazzz's ATTORNEYS June 18, 1963 G. A. PAGoNls 3,093,872

METHOD oF AND APPARATUS FOR FORMING AN INGoT 0F MOLTEN REACTIVE MATERIAL INVENTOR l ma m4 `,Z0 /44 /za 04 @forge Page1135 ATTORNEYS June 18, 1963 G. A. PAGoNls 3,093,872

METHOD OF AND APPARATUS FOR FORMING AN INGOT OF MOLTEN REACTIVE MATERIAL George il. Pagan/115' EY mW/@maw ATTORNEYS United States Patent 3,093,872 METHOD OF AND APPARATUS FOR FORMING AN INGOT OF MOLTEN REACTIVE MATERIAL George A. Pagonis, San Jose, Calif., assignor to Light Metals Research Laboratory, Inc., San Jose, Calif. Filed Sept. 30, 1959, Ser. No. 843,533 13 Claims. (Cl. 22--79) This invention relates generally to an apparatus for handling a molten material for forming an ingot thereof, and more specifically to an apparatus for conducting a high-temperature, molten, reactive material from a point of treatment to a receiving mold for forming an ingot.

Reference is made to applicants earlier applications, Serial No. 505,887, tiled May 4, 1955, for a Process for Treating Titanium Metals and now abandoned, and Serial No. 775,994, tiled November 24, 1958, for an Apparatus for Treating Titanium and Other Metals, of which the present .application is a continuation-impart and now Patent 3,079,451. These earlier applications relate to a method of and to an apparatus for producing substantially pure metals and ltheir base alloys in consistent homogeneity through the use of a novel sequence of operations in a novel multistage apparatus wherein the meta-l is tirst melted yand passed from stage to stage in its molten state. As disclosed in these earlier applications, the process is carried out by the continuous application of inert gas and vacuum in ra novel manner, the construction of the apparatus ybeing such as to preclude the entry of the ambient atmosphere at any stage during the operation thereof.

While the apparatus of the present invention may be used for torming an ingot of any conventional metal or alloy, it is particularly useful in the handling of reactive metals, such as titanium ,and other refractory rnetals, which at elevated temperatures have a high aiiinity for the oxygen and nitrogen in the atmosphere.

In the process as described in the earlier-tiled applications referred to above, the conditions of vacuum and inert atmosphere are employed throughout the entire system, including an ingot mold and connecting spout thereto from a orucible containing the molten metal. A valve is provided in the connecting spout adjacent the crucible, and this valve normally remains closed except during the pouring stage when the molten met-al is transferred `from the Crucible to the ingot mold. In the pouring operation it is important that atmospheric contaminants be completely excluded from contact with the molt-en metal and ingot until the latter has reached a nonreactive stage. It is also important that the temperatures of the ingot mold `and poured ingot be carefully controlled, both from the standpoint of prevention of thermal shock to the mold liner and for obtaining proper crystal structure in the cooled ingot.

It is .an object of this invention to provide a connection between the pouring spout and the ingot mold, which effectively precludes the lentry of ambient atmosphere into 4and the loss of the inert atmosphere from the mold and connecting spout.

It is a further object of the invention to provide a novel connection between the pouring spout and the mold whereby to retain both the mold and the connecting sp out in sealed condition when the mold is removed from the spout after receiving a charge of molten metal.

It is a further object of the invention to provide means for the evacuation of contaminating gases from the mold and spout and for the supply of an inert atmosphere thereto.

It is a further object of the invention to provide a novel separable valved connection between a connecting conduit and a rnold wherein the valve elements may tbe icc cooled simultaneously with the introduction of a relatively cool inert atmosphere into the mold.

It is a further object of the invention to provide a novel means for selectively heating or cooling an ingot mold.

It is a further object of the invention to provide a novel means for positioning an ingot mold in receiving relationship to a pouring spout and for raising and lowering said mold with relation to the end of sai-d spout.

Further, it is an object of the invention to provide means for temperature control Iof an ingot mold to avoid thermal shock to the mold and to facilitate the proper solidification 4of the mol-ten material.

`Other and further 4objects and advantages of this invention will become more apparent from a consideration of the following specification when read in conjunction with the annexed drawings, in which:

FIG. l is an elevational view showing the relationship of the pouring spout or conduit, the ingot mold, the separable valved connection between the conduit and mold, a mold-receiving and supporting member, and the means for raising and lowering the mold, certain parts of the cold and mold-receiving member appearing in section and the pouring spout being positioned for the beginning of a pouring operation;

FIG. 2 is a plan View of the separable valved connection;

FIG. 3 is a sectional View through the separable valved connection taken on the Iline 3 3 of FIG. 2 showing the valve members in their closed position;

FIG. 4 is a plan view of one of the housings of the separable valved connection as viewed on the line 4 4 of FIG. l, lshowing the valve member in its open position;

FIG. 5 is a vertical sectional View through the connecting spout or conduit, separable valved connection and mold, in one of the mold-iillin-g positions taken on the line 5-5 of FIG. 2; and

FIG. 6 is a View similar to FIG. 5, illustrating the valve elements in their closed position and the housings of the valved connection separated.

In the description which follows reference will be made, for purposes of exemplication only, to the productionV of titanium or titanium alloys in which an inert atmosphere of helium is employed. lt should be understood, however, that the apparatus and method could also be used in connection with other metals or refractory materials which are highly reactive at elevated temperatures in their molten state as well as with any conventional metal or other molten material, and that other inert gases could be employed. The references to titanium, titanium alloy, or helium in the Specification, therefore, are not intended as limitations, but are intended to be illustrative of the broad inventive concepts.

Referring to the drawings, in which identical parts are designated by the same reference characters, the system, as shown in FIG. l, comprises pouring spout C from a Crucible (not shown), a connecting member CM, a mold M, a mold-receiving member MRM, a platform P, and a hydraulic jack HI.

The pouring spout C is connected at its upper end through a valve to a Crucible, as shown in the earlierfiled applications Serial No. 505,887 and Serial No. 775,- 994, from which it receives pure molten titanium or titanium alloy, and the discharge or outlet end, designated by the reference numeral 10, extends vertically downward. The spout C includes an outer tubular shell l2, an inner lining 14, and an intermediate lining 16. The shell 12 is formed of steel, while the linings i4 and 16 are formed of a suitable refractory material capable of withstanding the high temperatures encountered.

As shown in FGS. 3, 5 and 6, the intermediate lining 3 16 is slightly shorter than the inner lining 14 and the shell 12, and is held in place by the upper end of a ring 20 of a stop collar 18. The ring 28 is externally threaded to matingly engage internal threads on the lower end of the shell 12. The lower end of stop collar 18 is provided with an internal flange 22 adapted to be received within a rabbet 24 in the lower end of the inner lining 14. The connecting member CM comprises a two-part valve assembly 26 including an upper valve housing 28 `and a lower valve housing 3ft.

The .upper valve housing 28, as shown in FIGS. 2, 3, and 6, is rectangular in form, having a flat upper surface including a hollow upstanding boss 32, having a bore 33, adjacent one end. The bore 33 in the boss has an internal diameter to provide a working llt about the outer surface of the shell 12, and includes a pair of spaced annulargrooves for sealing rings 34 adapted to prevent leakage of gases between the boss and the pouring spout C. The lower end of the bore 33 is rabbeted at 36 to receive an external flange 38 on the lower end of stop collar 18, as shown in FIGS. 3 and 6, to limit the downward sliding movement of the upper valve housing 28 on the outlet end 16 of the pouring spout C. The end of the valve housing 28 adjacent the boss 32 (to the left as viewed in FIGS. 5 and 6), includes a downwardly directe flange 42, and each side is provided with downwardly directed flanges 48, the ilanges 40 and 42 being interconnected and their lower edges being even, The other end of the housing 28 is turned up to form a flange 44. The flanges 40 and 42 form side walls and an end wall of the Valve housing, the other end Wall being formed by an upper housing plate 46 attached to the flange 44- by means of a plurality of cap screws 48 passing through aligned holes in the plate 46 and flange 44, and holes in a Teilon gasket 45 positioned between the ilange and plate. The lower surface of the housing 28, in the area surrounding the bore 33, is nished ofi smoothly to provide a valve seat Si), and is recessed to receive an O-ring 52.

A valve element 54 is slidably mounted within the upper valve housing 28, the sides and one end of the valve element having channels 56 adapted to engage longitudinally extending ribs 58 on the side and end flanges 48 and 42, which form guide means for the valve element.

The lower valve housing 3@ is generally rectangular in form, and includes, adjacent an end thereof, a downwardly extending boss 60, having a bore 62 therethrough. The other end of the housing has a downwardly extending ilange 64, which is adapted for connection with a housing plate 66, by means of plurality cap screws 70, which pass through aligned threaded holes in the end flange, the housing plate, and a gasket `68 of Teilon disposed between the flange and the housing plate. The valve housing 30 is provided with a pair of parallel side flanges 72 and an end flange 74 (FIG. 4), which flanges are Icontinuous .With the upper edge or the housing plate 66 to form four side walls of the valve housing, having an `open top for receiving a sliding valve element 78. The side and end flanges 72 and 74 have longitudinally extending ribs 76, which engage in longitudinally extending side and end channels 80 (FIG. 3) in the valve element 78 to form a guiding means for the valve element. An operating rod 82 is connected to the outer end of the valve element 78. This operating rod extends through an opening and a packing gland 84 in the lower housing plate 66, and is provided on its outer end with a handle 86 (FIG. l) by means of which the valve elements may be operated. The upper surface of the valve element 78 includes .a plurality of spaced, upwardly extending, dowels 88, which are adapted to engage an equal number of aligned recesses 90 in the lower surface of the upper valve element 54. The upper surface of the valve housing 30 surrounding the bore 62 is finished oil smoothly to provide a valve seat 92 for the valve element '78, and in- Cludes a groove to receive an O-ring 94.

As seen in FIGS. 4 and 5, portions of the ribs 58 and 76 are cut away at 96, to receive cam locks 98. Each cam lock 98 comprises a short cylindrical member which is eccentrically mounted on one end of a shaft 100 extending through the side flanges 40 and 72 of the upper and lower valve housing 28 and 30, respectively, the openings being sealed by means of packing glands 102. The outer ends of the shafts 10i) are equipped with operating cranks 104 by means of which the eccentrically mounted cam locks 98 can be oscillated. Springs 106 surround the shaft and act on the cranks 104 and the packing glands 102 to urge the shafts 100 outwardly. The cam locks 98 have a diameter equal to the width of the channels 56 and 881 in the valve elements 54 and 78, respectively, and are adapted to extend into these recesses so that when the cranks 104 are oscillated from the .postion shown in solid lines in FIG. l to the position shown in dotted lines, the cam locks 98, due to their eccentric mounting on the shafts 100, urge the valve elements 54 and 78 tightly against their valve seats 50 and 92, respectively.

The lower edges of the flanges 40 and 42 of the upper valve housing 28 and the upper housing plate 46, and the upper edges of the flanges 72 and 74 of the lower valve housing 30 and the lower housing plate 66, are each provided with a continuous channel 103. The channels 168 in the upper and lower valve housings 28 and 30 and in the upper and lower housing plates 46 and '66, are aligned, and adapted to receive an O-ring 110, which tightly ts within the grooves 108 to provide a fluid tight seal when the housing parts are brought together as shown in FIGS. 3 and 5.

The upper surface of the upper valve housing 28, near the end flange 44, is bored to receive a pipe tting 114, to which a flexible supply conduit 112, having a valve 113 (FIG. 2), is connected.

Referring to FIGS. l, 3, 5 and 6, the mold M comprises a cup-shaped outer shell 1,16 of steel, which is lined with a refractory lining 118, extending to a point short of the upper end of the shell, where it contacts the lower end of the boss 60. Refractory lining 118, in the operation of the process on titanium metal or alloy, may be formed by heavily spraying the interior face of shell '116 with a fine refractory material comprising from about 75-90% 1h02, 6-10% HfOz, 37% ZrO2 and 1-3% [203. The upper end of the shell is flanged at 120, and the lower surface of the lower valve housing 30 is grooved to receive an O-ring 12,2 to form a seal between the valve housing and the flange 120.

Locking means are provided for selectively securing valve housings 28 and 30 together and to the shell 1116 of the mold. Thus, flange is provided with four circumferentially spaced threaded bores to receive the lower ends of threaded stud bolts 124. Lock nuts .126 are tightly screwed about the bolts against the flange 120 to prevent unscrewing of the stud bolts. Each stud bolt carries, in vertically spaced relation, a lower clamping lever 128, held in proper position by upper and lower lock nuts 130, and an upper clamping lever 132, held in place by a lower lock nut I134 and an upper wing nut 36. These levers are adapted to be swung into position over the upper edges of the flanged sides andthe ends of the valve housings 28 and "30, as shown in FIGS. l and 5, to clamp the valve housings and the mold in fluid- -tight relation.

As shown in FIGS. 2, 3 and 4, the lower valve housing 36 includes a pair of opposed passages i138 and 140, which enter the side flanges 72 in a horizontal direction and extend downward in an oblique direction through the boss 62, terminating in the lower end of the boss as shown in FIG. 3. The passages 138 and 140 are provided with fittings 141 and 142 to which flexible conduits 143 and 144, having valves 145 and 145a, are connected. These conduits may be readily disconnected so that the mold and lower housing 30 can be removed from the vicinity of the pouring spout.

Referring to FIG. l, the mold M is adapted to be removingly litted within a mold receiving member MRM. This mold receiving member comprises a cup-shaped element 146 of refractory material, in which is embedded a continuous copper tubular element 148 disposed adjacent the inner wall of the member 146. The copper tubular element 148 includes an inlet 150 and an outlet i152, extending outside the cup-shaped element 146, the inlet 150 being adapted to be connected through a exible hose (not shown) with a source of cooling iiuid, which passes through a tubular element 148 and discharges :from the outlet 152. A pair of electrical conductors 154 are connected to the inlet and outlet '158 and 152, respectively. These conductors are adapted to be connected to a source of high frequency, alternating current for induction heating for a purpose to be described hereinafter.

The mold receiving member MRM is carried by a platform P, comprising a base 156 provided with centering means 158 to receive the lower end of the cup-shaped element E146, in order to properly align the mold and the upper and lower housings 23 and 30 during assembly for a pouring operation as described below. The platform P is supported by a hydraulic jack HI, comprising a cylinder 16d, a reciprocating piston 162, and a piston rod 164 connected to the base 156 of the platform. The cylinder 168 includes upper and lower iluid connections A166 to receive and exhaust pressure fluid for raising and lowering the platform and the mold M supported thereon.

The operation is as follows:

It may first be assumed that it is desired to ill the mold M with molten material from the crucible, not shown, by way of the pouring spout C. The clamps 128 and 132 are set, as shown in FIG. l, to securely fasten the connecting member CM to the mold and the valve housings 28 and 38 together. The valve elements 54 and 78 are moved to their open position, as shown in FIG. 5, by pulling the handle 86 outwardly until the outer ends of the valve elements are stopped by striking the housing plates 46 and 66. The dowels 88 in the lower valve elements 78 are in engagement with the recesses 98 in the upper valve element 54, so that the two valves are compelled to move together. When the valves are in their open position, as shown in FIG. 5, the mold `M and platform P are raised by admitting pressure fluid to the space below the piston 162 and exhausting fluid from the space above the piston. As the pouring spout C is fixed against movement, and in view of the sliding connection between the boss 32 on the upper valve housing 28 and the outlet end 10 of the connecting conduit C, the mold M and the connecting member CM are moved upwardly relative to the outlet end 1t) of the spout C until the lower or outlet end 16 is disposed slightly above the bottom of the mold in the position shown in HG. l. Flexible conduit I144 is connected with an exhaust pump or other source of Vacuum, while the other conduit 1435` is connected with a supply of inert gas under pressure, such as helium, for example. At the same time the conduit i112 to valve housing 26 is connected with the common supply of inert gas. After the mold and valve assembly have been evacuated through line 144, valve 145a being open, inert gas is admitted to the valve housings and mold by opening valves 113 and 145. As a result of this operation, the interior of the mold, the interior of the pouring spout C, and the interior of the connecting member CM, are flushed of contaminating gases and are iilled with an inert atmosphere of helium at a relatively low gage pressure, which assures the continued exclusion of any other gas that may react with the molten material to be delivered into the mold.

Meanwhile, the mold M is inductively preheated to a temperature in the neighborhood of 1260* lto l300 F. by passing a high frequency alternating current through the tubular element 148 by means of the conductors 154.

Such preheating continues until the mold and the lining reach the desired temperature.

The valve in the pouring spout C, adjacent the Crucible mentioned above and disclosed in application Serial No. 505,887, may then be opened to permit the discharge of the molten titanium or titanium alloy from the crucible, at a controlled discharge rate.

When the valve in the pouring spout C is opened, the molten material, which in the case of titanium metal may be at a temperature in the order of 30010o `F., flows into the mold by force of gravity. `Because of the preheated condition of the mold and the position of the outlet end 10 of the pouring spout C in close proximity `to the bottom of the mold, the material flows into the mold without splashing and substantially without thermal shock. rlhe heating of the mold by means of the tubular element 148, as described above, continues during the initial rfilling of the mold. Filling of the mold proceeds until a pool is collected at the bottom of the mold, whereupon the fluid is admitted to the upper end and discharged from the lower end of the hydraulic jack Hl' to lower the mold relative to the discharge end 10 of the connecting conduit. The rate of lowering of the mold can be regulated by any known means. When the mold M contains a substantial amount of the molten material, for example, when it is one-uarter to one-half full, heating by lthe tubular element 148 is discontinued and cooling of the mold and molten material can be initiated by circulating a cooling liuid, such as air or liquid, through the tubular element 14S to bring about uniform solidification. As vfilling of 4the mold continues, the mold M and the connecting member CM are lowered until the outer ilange 38 of the stop collar 18 engages the rabbet 36 in the lower end of boss 32, which is effective to limit the downward movement of the mold and the connecting member. The molten material in the mold is preferably kept under a constant inert gas pressure until it has solidified and cooled. In the case of titanium, inert gas pressure should be maintained until a temperature 800 F. has been reached.

If desired, -the valve g -in the conduit 144- which is connected with the source of vacuum can be closed during pouring, or the valve can be partially closed so that there is a continuous supply of linert gas by way of the conduit 112 and conduit 144 which is at a rate sufficient -to maintain the desired pressure within the parts. This mode of operation has the advantage of permitting the relatively cool supply of insert gas admitted by conduit 112 to pass over and about the valve elements 54 and 78, and about the cam locks 98, to protect them from the high temperature of the molten material. Preferably, the pressure is kept slightly above atmospheric and is maintained at a constant value during the pouring.

When the mold M is filled, the' valve in the pouring spout C at the Crucible may be closed, and the valve elements 54 and 76 may be moved toward their closed position by pushing on the handle 86 until the nibs 58 and 76 engage the channels 56 yand 80 in the ends of the sliding valve members. The cranks 104 may then be oscillated from the position shown in solid lines in FIG. 2 to the position shown in dotted lines, which oscillates the eccentrically mounted cam locks 98 to forcibly urge the valve members 54 and 78 against their valve seats 50` and 92, respectively, providing a fluid tight seal between the valve elements and the discharge end 10 of the pouring spout on one hand, and the open top of the mold M on the other hand, and at the same time locking the valve ele ments against inadvertent opening movement. The mold M may then be removed by separating the valve housings 28 and 30 so that the upper housing 28 remains with the pouring spout C and the lower housing 3d is removed with the mold. To facilitate such separation, the wing nuts 136 may be loosened or removed, which enable the upper clamping levers 132 to be swung out of the way of the upper housing process. `ing member MRM for any desired length of time, where `in the upper and lower housings. lso brought together, the clamping levers 132 may then @,osasve 23, or removed, as shown in FIG. 6. The valves 113, 145 and 145e are closed, and the piston 162 in the hydraulic jack HJ may then be lowered, whereby the upper and lower valve housings 28 and 30 are separated, as shown in FIG. 6. "ihe mold M may be removed -and when the ingot has reached a temperature below reactive temperature, lower valve `housing 39 can be removed for placement on another mold for repeated operation. lf desired, a number oi lower valve housings can be provided to speed up the The mold may be left Within the mold receiv it may be cooled at a selected rate by the external cooling means. Both the presence of inert gas under pressure and controlled cooling rate beneiicially iniiuence proper .crystal structure in the product ingot.

When it is desired to form another ingot, the mold M and the mold receiving member MRM are mounted -on the platform P, and the hydraulic jack Hl is operated to raise the platform. The centering means 158 assures that the mold is properly aligned with the connecting yconduit C, and the valve elements 54 and 73, being locked -by means of the cam locks 98, assure that the dowels S8 enter the recesses 90 land that the housings ZS and Vit) are brought together in proper relationship so that the O-ring 21.10` is properly received within the grooves 108 When the parts are again be brought to bear against the upper surface of the upper housing 28 and tightened by means of the .Wing nuts 136. The valves in the conduits 112, 142 and 144 may then be opened, and the valve members 54 and 70 opened by drawing on the handle 86, as described iabove.

It will be understood that various changes may be made in details of construction yand in the arrangement yof parts of the system disclosed herein without depart- 'ing from the principles of the invention and the scope of the annexed claims. For example, the ingot mold may itself be provided with a suitable temperature control means, and other modifications generally as described Yand shown in copending application Serial No. 505,887

`opening within the mold; a connecting member connecting said mold and conduit in gas-tight relation, sald conuecting member comprising an upper valve housing hav- ,ing a bore slidably receiving -said conduit; se-aling means 55 providing `a gas-tight sliding t between said bore and the Vouter periphery of said conduit; a lower valve housing having a gas-tight but separable connection with said upper valve housing and having a bore registering with the bore of the upper vaive housing and also adapted to receive :said conduit, said lower valve housing being tixed to said mold; a pair of slide valve members, one slide valve khousings being movable axially with respect to said conduit lto position said discharge opening at selected distances trom the bottom of the mold during a mold-tilling operation and within the upper valve housing above said valve members at the end of -a mold-l-ling operation, said val-ve housings being separable together with their respective valve members, the upper valve housing being adapted to remain with said CGnduit with its valve closing said discharge opening and the lower valve housing being adapted to remain with the mold with its valve closing said open top.

2. The apparatus of claim l including means to move the mold and associated valve housings axially relative to said conduit to vary the distance between the discharge opening of said conduit yand the bottom of said mold.

3. The apparatus of claim 1 including a member for receiving said mold, said member including a tubular 10 element in heat exchange relation to said mold, and means to supply a heat exchange Huid to said tubular element.

4. The apparatus of claim 3 in which said tubular element is of electrically-conductive material, and means for `connecting Asaid `tubular element to a source of high frequency alternating current.

5. The apparatus of claim l including means to supply an inert atmosphere within said mold and to withdraw gases lfrom said mold.

6. The apparatus of cla-im 5 in which the supply means for inert atmosphere includes a passageway through one of said valve housings.

7. The apparatus of claim il including cooperating means carried by said conduit and said upper valve housing to limit relative sliding movement of said hou-sing with respect to said `conduit so as to prevent removal of said upper valve housing from said conduit.

8. The apparatus of claim 7 wherein said means carried by said conduit and upper valve housing to lim-it relative sliding movement of said housing with respect to said conduit comprise a flange on said conduit adjacent said discharge opening and a shoulder vvithin the bore of said upper valve housing above its associated valve member for engagement with said iiange.

9. The apparatus of claim l wherein each valve housing includes a valve sea-t, said valve members are slidable over their respective seats and said valve housings each Y include locking means lfor forceably urging their respective valve members against their respective seats to seal the end of the conduit and the mold, respectively after a casting operation.

10. The apparatus of claim 9 including means within said valve housings interconnecting said valve members for concurrent transverse sliding movement over their respective seats, said interconnecting means being separable upon movement of said valve members in a direction normal to said transverse sliding movement.

11. A separable valve assembly `for, providing a gastight connection between a supply conduit and a mold 00 during a casting operation, comprising: an upper valve housing having `a bore adapted to receive said supply conduit, the upper portion of said bore being of reduced diameter to provide a close sliding tit with the outer periphery of said conduit and having sealing means adapted to provide a gas-tight but slidable connection with said supply conduit; a lower valve housing having a gas-tight but separable connect-ion with said upper valve housing and having a bore registering with the bore of said upper valve housing and also adapted to receive said supply conduit, said lower valve housing being adapted to be secured in fixed gas-tight relation to the top of said mold; a pair of slide valve members, one of said valve members being carried by each val-ve housing and each valve member being movable between open and closed positions opening and closing the bore of its respective housing; each valve housing having a valve seat receiving its respect-ive valve member in said closed position; means for moving said valve members :between said open and closed positions; means carried by each valve housing to forceably urge yand lock each valve member against its seat,

said valve housings being separable together with their respective valve members with the upper valve housing being adapted to remain with said supply conduit with its valve closing the end thereof and the lower valve housing gage a recess in the other valve member. 

1. AN APPARATUS FOR CASTING AN INGOT OF MOLTEN MATERIAL, COMPRSING: AN INGOT MOLD HAVING AN OPEN TOP; A DOWNWARDLY-DIRECTED CONDUIT FOR DELIVERING SAID MOLTEN MATERIAL INTO SAID MOLD, SAID CONDUIT HAVING A DISCHARGE OPENING AT ITS LOWER END AND BEING RECEIVABLE THROUGH THE OPEN TOP OF SAID MOLD TO POSITION SAID DISCHARGE OPENING WITHIN THE MOLD; A CONNECTING MEMBER CONNECTING SAID MOLD AND CONDUIT IN GAS-TIGHT RELATION, SAID CONNECTING MEMBER COMPRISING AN UPPER VALVE HOUSING HAVING A BORE SLIDABLY RECEIVING SAID CONDUIT; SEALING MEANS PROVIDING A GAS-TIGHT SLIDING FIT BETWEEN SAID BORE AND THE OUTER PERIPHERY OF SAID CONDUIT; A LOWER VALVE HOUSING HAVING A GAS-TIGHT BUT SEPARABLE CONNECTION WITH SAID UPPER VALVE HOUSING AND HAVING A BORE REGISTERING WITH THE BORE OF THE UPPER VALVE HOUSING AND ALSO ADAPTED TO RECEIVE SAID CONDUIT, SAID LOWER VALVE HOUSING BEING FIXED TO SAID MOLD; A PAIR OF SLIDE VALVE MEMBERS, ONE SLIDE VALVE MEMBER BEING CARRIED BY EACH VALVE HOUSING AND EACH VALVE MEMBER BEING MOVABLE BETWEEN OPEN AND CLOSED POSITIONS OPENING AND CLOSING THE BORE OF ITS RESPECTIVE HOUSING; MEANS FOR MOVING SAID VALVE MEMBERS BETWEEN SAID OPEN AND CLOSED POSITIONS; SAID INGOT MOLD AND VALVE HOUSINGS BEING MOVABLE AXIALLY WITH RESPECT TO SAID CONDUIT TO POSITION SAID DISCHARGE OPENING AT SELECTED DISTANCES FROM THE BOTTOM OF THE MOLD DURING A MOLD-FILLING OPERATION AND WITHIN THE UPPER VALVE HOUSING ABOVE SAID VALVE MEMBERS AT THE END OF A MOLD-FILLING OPERATION, SAID VALVE HOUSINGS BEING SEPARABLE TOGETHER WITH THEIR RESPECTIVE VALVE MEMBERS, THE UPPER VALVE HOUSING BEING ADAPTED TO REMAIN WITH SAID CONDUIT WITH ITS VALVE CLOSING SAID DISCHARGE OPENING AND THE LOWER VALVE HOUSING BEING ADAPTED TO REMAIN WITH THE MOLD WITH ITS VALVE CLOSING SAID OPEN TOP. 